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s390/kvm: Provide a way to prevent reentering SIE

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Lets provide functions to prevent KVM from reentering SIE and
to kick cpus out of SIE. We cannot use the common kvm_vcpu_kick code,
since we need to kick out guests in places that hold architecture
specific locks (e.g. pgste lock) which might be necessary on the
other cpus - so no waiting possible.

So lets provide a bit in a private field of the sie control block
that acts as a gate keeper, after we claimed we are in SIE.
Please note that we do not reuse prog0c, since we want to access
that bit without atomic ops.

Signed-off-by: Christian Borntraeger <borntraeger@de.ibm.com>
Acked-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Gleb Natapov <gleb@redhat.com>
This commit is contained in:
Christian Borntraeger
2013-05-17 14:41:35 +02:00
committed by Gleb Natapov
parent 95d38fd0bc
commit 49b99e1e0d
5 changed files with 40 additions and 2 deletions
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4
arch/s390/kernel/entry64.S
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@@ -958,7 +958,9 @@ sie_loop:
lctlg %c1,%c1,__GMAP_ASCE(%r14) # load primary asce
sie_gmap:
lg %r14,__SF_EMPTY(%r15) # get control block pointer
oi __SIE_PROG0C+3(%r14),1 # we are in SIE now
oi __SIE_PROG0C+3(%r14),1 # we are going into SIE now
tm __SIE_PROG20+3(%r14),1 # last exit...
jnz sie_done
LPP __SF_EMPTY(%r15) # set guest id
sie 0(%r14)
sie_done: